GIS Modeling to Climate Change Adaptation by Reducing Evaporation in Water Reservoirs: Smart Location Technique of Minimal Evaporation Reservoirs (GIS-MER)

Abstract

The ideal emplacement of reservoirs has been traditionally determined by means of GIS tools to prospect large areas applying criteria related to rainfall, substrate impermeability or economic and social viability. More recently, geomorphometric characteristics have been added to determine more suitable locations for dams and reservoirs depending on their dimensions. This study presents a fully automatized ArcGIS Pro model, suitable for working with several digital elevation model resolutions and for evaluating best potential reservoir locations to reduce evaporation losses. Here, a smart location strategy to preserve water resources is used based on the premise that the higher the ratio of water stored to water surface area of the reservoir, the lower the water evaporation. The model was tested in two dissimilar basins in the province of Cadiz (SW Spain) and the results are compared with the nearby existing reservoirs. The methodology presented in this paper allows selecting the most suitable sites where it is possible to build a reservoir with a water surface smaller than other reservoirs but also able to hold an equal or greater volume of water; this also allows reducing the area occupied by the reservoir. As an example, in the first study case presented in this paper, a new reservoir could store 30.7 m3/m2 versus the current 9 m3/m2 stored in the nearby existing reservoir. This may reduce the flooded area from 25.4 to just 6.7 km2.